(USA TODAY) NASCAR met with teams, crew chiefs and drivers for about 17 minutes Saturday afternoon at Chicagoland Speedway to discuss ethics and rules for its on-track racing product after a week of controversy around race fixing heading into its signature playoff event.

The news media was not allowed in the meeting.

Among the rules changes announced that will take effect during Sunday's opening Chase for the Sprint Cup race: Teams and drivers cannot offer positions for benefit, ask another to give up position, cause an intentional caution or cause an intentional wreck.

Also, a camera will be placed on the spotter stand to help NASCAR monitor activity.

Only one team spotter will be allowed on the stand and only analog radios will be used on the stand. Digital radios are now forbidden there.

"Today's technical bulletin addresses the subject of team(s) artificially altering the outcome of a race and the level of reaction that this will receive from NASCAR," said Robin Pemberton, NASCAR Vice President of Competition, in a statement. "We reinforced this issue to the teams in our meeting earlier today and conveyed what is considered unacceptable in our officiating of the event."

After NASCAR reset its Chase for the Sprint Cup field for a second time this week by making the unprecedented move of expanding the 12-man field to include a 13th driver -- Jeff Gordon -- chairman Brian France and president Mike Helton said the meeting would make clear to all what the code of conduct is and where the line should be drawn for teams working together on track.

"Circumstances happened that are unhelpful in the credibility category. There's no doubt about that," France said after Saturday's meeting.

On the rules to help curb teamwork, France said:

"This is what they (the drivers) want. They don't like team rules and they don't like some of the things that have gone on in the past."

Teams often help each other, cutting deals within organizations or under the same manufacturer umbrella -- Ford drivers helping Ford drivers, for example -- to improve track position or pick up a point or lead a lap when needed.

But a week ago, during the Chase-setting race at Richmond International Raceway, NASCAR and many drivers believed Michael Waltrip Racing overstepped that line by trying to fix the race outcome and get one of its drivers -- Martin Truex Jr. -- into the championship field.

NASCAR docked all three MWR drivers 50 points, fined MWR $300,000, put team general manager Ty Norris on probation and removed Truex Jr. from the field, replacing him with Ryan Newman.

After more in-race audio surfaced Wednesday that pointed to possible collusion between Front Row Motorsports and Penske Racing, NASCAR added Gordon to the field, saying he didn't have a fair chance to make the Chase.

Crew chief Paul Wolfe, who guides the No. 2 Ford of reigning Cup champion Brad Keselowski, said after Saturday's meeting: "I think everyone should have a pretty clear understanding of what that (line) is now.

"If you go out there and run 100% to your ability and run a normal race, then everything will be fine."